Comprehensive Experimental Study on the Fire Hazards of LiPF6-Based Electrolytes

Electrolytes are a primary flammable component in lithium-ion batteries and the main source of heat release during battery burning. Comprehensive investigations into the overall fire hazards of electrolytes remain scarce. In this study, systematic experiments were conducted to characterize the fire hazards of different LiPF6-based electrolytes, including TG-DSC analysis, self-extinguishing time experiments, auto-ignition temperature measurements, and hot-surface ignition experiments. Then, the fire hazard characteristic parameters obtained were analyzed, and the correlations between these parameters were revealed. The TG-DSC analysis indicated that the temperature at 5% mass loss, the peak mass loss temperature, and the exothermic peak temperature increased with the addition of EMC or DMC but decreased as the content of EMC and DMC increased. Moreover, it was found that the lowest hot-surface ignition temperatures of the electrolytes were higher than the auto-ignition temperatures. The comprehensive analysis of fire hazard parameters showed that the electrolytes with lower thermal stability exhibited lower self-extinguishing times. Finally, the electrolytes with relatively low thermal stability exhibited an elevated lowest hot-surface ignition temperature. These findings could provide valuable references for the risk assessment and safety protection of fire hazards related to lithium-ion battery electrolytes.